Count full hours that meet a criteria?

Detlef_Lewin Sorry, but this is not so simple.

I want for the computer to compare the range of hours from users input to a range of hours set in the criteria. As in the example above: User inputs start 14:00 and end 22:00, criteria is valid between 18:00 and 24:00. Therefore 4 hours match with the users input. Computer should output 4. 

With specific weekdays I want the user to also input the weekday and have the computer compare the weekday to another set criteria. Say criteria 1 counts between 18:00-22:00 mon-fri. Criteria 2 counts between 22:00-06:00 mon-fri. Criteria 3 counts 00:00-24:00 sat-sun. Should the user input start 19:00 friday and end 08:00 saturday, computer should output criteria 1: 3 hours, criteria 2: 2 hours, criteria 3: 8 hours. 

Hope this clarifies.